KR20190038493A - Metamaterial nanocomposite with high refractive index having broadband feature - Google Patents

Abstract

The present invention relates to a high refractive index meta-material nanocomposite structure having broadband characteristics in wavelength bands of visible light, ultraviolet light and/or infrared light. The high refractive index meta-material nanocomposite structure comprises unit structures including nanoparticles and a host material, wherein the unit structures are densely arranged in a three-dimension.

Description

METAMATERIAL NANOCOMPOSITE WITH HIGH REFRACTIVE INDEX HAVING BROADBAND FEATURE < RTI ID = 0.0 >

The present invention relates to a high refractive index meta material nanocomposite structure having broad band characteristics and an optical film comprising the meta material nanocomposite structure.

The development of the semiconductor industry is based on improving the precision of microprocessing in semiconductor processes. The key technology of the microfabrication of semiconductors depends on how finely the pattern of the etching resist in the photolithography process can be finely adjusted. In order to finely etch the pattern, it is necessary to improve the resolution of the optical system Do. Currently, the best photolithography device is an excimer laser, which can produce devices with a minimum wiring width of 14 nm using light of wavelengths of 248 nm and 193 nm. However, in order to exceed this limit, other alternatives are needed.

The oil immersion technique uses a transparent oil having a specific optical and viscosity characteristic between the objective lens and the sample in an optical microscope and can reduce the wiring width to several nanometers in accordance with the improvement of the oil property It is expected. Currently, highly purified water is used instead of oil in semiconductor processes.

(2), where? Is the wavelength of the light, NA is the numerical aperture of the lens, NA is the numerical aperture of the lens, nsin? ₀ where n is the refractive index of the material filling between the lens and the pattern, such as oil or water, and? ₀ is the angle seen by the objective lens as seen in the sample. In the actual semiconductor process, a line width smaller than the size determined in the simple relation is obtained by applying various techniques such as double exposure and resist development condition control in order to further reduce the line width even a little. However, Therefore, it is possible to obtain a smaller line width by basically reducing the resolution represented by the above relational expression. From the above two relations, it can be seen that the resolution of the fine pattern size is inversely proportional to the refractive index of the oil between the objective lens and the sample, and that a high resolution requires a high refractive index immersion oil. However, in this case, the development of a high refractive index oil, which is an optical characteristic of the oil to be improved, is currently being delayed due to the lack of high refractive index oil and the difficulty in making it.

In the past several years, negative refractive index meta materials having negative refractive index have been developed by making both the effective permittivity and the effective permeability both negative in various wavelength ranges from microwave to visible light. However, studies on metamaterials with high refractive indexes in the opposite extreme have been relatively under-researched, focusing on the theoretical feasibility. Among the conventional studies, the approach using electrical resonances in isolated ring resonators showed an increase in refractive index, but such designs inherently have a high refractive index in a narrow frequency band. The metamaterial exhibits strong dispersion characteristics near the resonant frequency and maintains the desired refractive index only in the narrow frequency region. A metamaterial made of an array of capacitors with subwavelengths (wavelengths) has been proposed to have a high dielectric constant in the broadband, but this has also been problematic due to the strong antimagnetic effect of suppressing the magnetic permeability value. Recently, a broadband high refractive index meta-material has been theoretically proposed to reduce this effect. However, the proposed structure is not an easy implementation because of its three-dimensional characteristics.

Korean Patent Laid-Open Publication No. 2012-0007819 discloses a meta material and a method of manufacturing the same, and discloses a meta material including a nanopattern structure having a negative refractive index in a natural state and a manufacturing method thereof.

One embodiment of the present invention is to provide a nanometer-sized nanoparticle having a broad refractive index in visible light, ultraviolet, and / or infrared wavelength band by closely-packed nanoparticles of a size much smaller than a wavelength, A composite structure and an optical film comprising the meta-material nanocomposite structure.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

The first aspect of the present invention provides a meta-material nanocomposite structure comprising unit structures including nanoparticles and a host material, wherein the unit structures are arranged in three dimensions.

The second aspect of the present invention provides an optical film comprising the meta-material nanocomposite structure according to the first aspect of the present invention.

According to one embodiment of the present invention, a high-refractive-index meta-material nanocomposite structure exhibiting broad band characteristics can be provided. The unit structure of the meta-material nanocomposite structure according to an embodiment of the present invention is formed to have a size smaller than a wavelength (about 1/10 of a wavelength in a vacuum), and the unit structure is three- packed) so that the entire structure can have the same optical effect as a single material with a high refractive index.

According to an embodiment of the present invention, the size of the nanoparticles corresponding to or smaller than the skin depth of the nanoparticles induces magnetic penetration into the nanoparticle portion, so that the effective permeability of the nanoparticle It is possible to achieve a high refractive index. In addition, the permittivity can be freely adjusted through a simple structure without a noticeable change in the permeability by changing the width of a gap, which is an interval between adjacent nanoparticles, while maintaining the size of the unit structure at a constant value. That is, high dielectric constant and high refractive index can be achieved by reducing the width of the gap, and since the control of the permittivity and permeability is important in designing the impedance and other optical properties of the material, To immersion lenses, waveguide couplers, modulators, photodetectors, and energy devices.

According to an embodiment of the present invention, the meta-material nanocomposite structure has an effect of overcoming bandwidth limitation of other metamaterials directly dependent on surface plasmon resonance.

According to one embodiment of the present invention, since the meta-material nanocomposite structure has the same effect for other nanoparticle type and lattice type, it provides a possibility for a large number of bottom-up nanoparticle synthesis methods in place of expensive and complex top- .

1 is a schematic diagram (a) of a cubic meta-material nanocomposite structure densely arranged three-dimensionally and a schematic diagram (b) showing a metal particle size condition for achieving a high refractive index in one embodiment of the present invention.
2 is a schematic of a finite difference time domain method (FDTD) simulation in one embodiment of the present application.
3 is material data used in the FDTD simulation in one embodiment of the present invention.
FIG. 4 is a graph showing an image [(a), (d), and (g)] showing the unit structure of the meta-material nanocomposite structure and the complete electrical conductor in one embodiment of the present invention; (c), (f), and (i) of the unit structures [(b), (e), and (h)
5 (a) and 5 (b) are FDTD simulation results showing effective permittivity, effective permeability, and effective refractive index of a gold meta-material nanocomposite structure made of SiO ₂ as a host material in one embodiment of the present invention.
6A to 6F are graphs showing a relationship between an asymptotic value [(a) and (a) of the gold conductor metamaterial nanocomposite structure in which the width of the gap is changed under a constant unit structure size, (b) and (e), and the refractive indices [(c) and (f)].
7 (a) to 7 (d) are schematic views showing the cubic nanoparticles in the cubic lattice and the spherical nanoparticles in the hexagonal lattice in the embodiment of the present invention [(a) and (b) FDTD simulation results [(c) and (d)].
8 is an image showing a process of manufacturing a hole pattern by block copolymer lithography in one embodiment of the present invention.
9 is an image showing an ion milling process of the aluminum meta-material nanocomposite structure in one embodiment of the present invention.
10 (a) to 10 (d) are SEM images showing an aluminum meta-material nanocomposite structure in one embodiment of the present invention.
11 (a) and 11 (b) are AFM images showing an aluminum meta-material nanocomposite structure in one embodiment of the present invention.
12 is a UV-VIS spectrometer spectrum showing the measured transmittance of the aluminum meta-material nanocomposite structure in one embodiment of the present invention.
13 is a graph of FDTD simulation showing calculated transmittance of the aluminum meta-material nanocomposite structure in one embodiment of the present invention.
14 is a graph of an FDTD simulation showing the derived effective refractive index of the meta-material nanocomposite structure in one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

Throughout this specification, when a member is " on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout this specification, when an element is referred to as " including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The terms " about ", " substantially ", etc. used to the extent that they are used throughout the specification are intended to be taken to mean the approximation of the manufacturing and material tolerances inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure. The word " step (or step) " or " step " used to the extent that it is used throughout the specification does not mean " step for.

Throughout this specification, the term " combination (s) thereof " included in the expression of the machine form means a mixture or combination of one or more elements selected from the group consisting of the constituents described in the expression of the form of a marker, Quot; means at least one selected from the group consisting of the above-mentioned elements.

Throughout this specification, the description of "A and / or B" means "A or B, or A and B".

Throughout this specification, the term "metamaterial" refers to a material made of an array of mata atoms designed with a metal or dielectric material sized to a size much smaller than the wavelength of light, It means that it is artificially designed and made to have optical properties.

Throughout this specification, the term "close-packed" refers to a state in which nanoparticles or unit structures are uniformly arranged in three dimensions with a uniform unit structure size and gap width in the host material . The densely arranged nanoparticles and densely arranged unit structures according to the present invention exhibit broadband characteristics from the visible light to the ultraviolet and / or infrared wavelength band and have a high refractive index. The nanoparticle and the unit structure of the unit structure and the width of the gap may be several nanometers or less, but the present invention is not limited thereto.

Throughout this specification, the term "skin depth " refers to a depth indicating how far an electromagnetic wave can penetrate from the surface of the medium. In the medium, the current density tends to become maximum near the surface of the medium depending on the skin effect, and tends to decrease as it penetrates into the conductor. The current mainly flows at the "surface" of the conductor between the outer surface and the level called the skin depth, and thus the penetration depth is more specifically defined as the current density or electric field at the surface of 1 / e 37%).

Throughout this specification, the term "refractive index " refers to the rate of speed of a wave traveling in two media as the light travels from media to another media. The refractive index differs according to the wavelength. At the interface of the medium with different refractive index, the light bends according to Snell's law and partly reflects according to the incident angle. The refractive index can be expressed by the square root of the relative permittivity and the relative permeability with respect to the following Equation 1. As the refractive index value increases, the resolution, which is the ability to distinguish two objects from each other in an optical device, The resolution is increased because it is improved:

 [Formula 1]

Hereinafter, embodiments of the present invention are described in detail, but the present invention is not limited thereto.

The first aspect of the present invention provides a meta-material nanocomposite structure comprising unit structures including nanoparticles and a host material, wherein the unit structures are arranged in three dimensions.

In one embodiment of the present invention, the unit structure may be three-dimensionally closely packed.

In one embodiment of the present invention, the meta-material nanocomposite structure may have a high refractive index in a wavelength band selected from visible light, ultraviolet light, infrared light, and combinations thereof, but may not be limited thereto. For example, the meta-material nanocomposite structure may exhibit a high refractive index by controlling the size of nanoparticles of the meta-material nanocomposite structure and / or the width of a gap that is an interval between adjacent nanoparticles, .

The high refractive index meta material proposed for the conventional terahertz frequency has a disadvantage that it is difficult to apply directly at visible wavelength due to the difficulty of nano fabrication due to complicated structure. However, the high-refractive-index meta-material nanocomposite structure according to one embodiment of the present invention can be formed by appropriately selecting the width of the gap that is the gap between the nanoparticle size and the adjacent nanoparticles in the unit structure, It is possible to improve the effective permittivity and the refractive index.

In one embodiment of the present invention, the unit structure may be isotropically or anisotropically and densely arranged three-dimensionally.

In one embodiment of the present invention, the meta-material nanocomposite structure may have a maximum refractive index of about 1.5 or more at a wavelength of about 200 nm or less, but the present invention is not limited thereto.

In one embodiment of the present invention, the meta-material nanocomposite structure may have a maximum refractive index of about 2 or more at an ultraviolet wavelength of about 200 nm to about 400 nm, but the present invention is not limited thereto.

In one embodiment of the present invention, the meta-material nanocomposite structure may have a maximum refractive index of about 4 or more at a visible light wavelength of about 400 nm to about 700 nm, but the present invention is not limited thereto.

In one embodiment of the present invention, the meta-material nanocomposite structure may have a maximum refractive index of about 5 or more at an infrared wavelength of about 700 nm or more, but the present invention is not limited thereto.

FIG. 1 (a) is an image showing an example of a densely three-dimensionally arranged cubic meta-material nanocomposite structure included in a dielectric host material for achieving a high refractive index according to an embodiment of the present invention. As in FIG. 1, the blue and gray regions indicate dielectric and metal, respectively. In Fig. 1 [b (i)] surrounded by the dotted green rectangle, the arrows indicate the electric field and the field intensity is weakened by the electrons of the metal. In Fig. 1 (b (ii)), the length of the arrow indicates the intensity of the magnetic field and the intensity of the electromagnetic wave is weakened when the magnetic field penetrates into the metal.

In one embodiment of the present invention, the size of the nanoparticles in the unit structure may correspond to or smaller than the penetration depth of the nanoparticles, but may not be limited thereto.

In one embodiment of the present invention, the depth of penetration may vary depending on the kind of the nanoparticles, but may not be limited thereto. Since the penetration depth is not only a metal but also a doped semiconductor or a material having a negative real part of a permittivity, the magnetic field can not enter the inside and exponentially decreases with distance from the surface. Therefore, Lt; RTI ID = 0.0 > penetration depth. Here, the penetration depth is a depth indicating how far the electromagnetic wave can penetrate from the surface of the medium, and the intensity of the electromagnetic wave decreases by 1 / e when it is penetrated by the penetration depth. When the nanoparticles have a size corresponding to or smaller than the penetration depth, the magnetic field is distributed substantially uniformly throughout the unit structure, which prevents the effective permeability of the meta-material nanocomposite structure from decreasing, Meta-material nanocomposite structures can be created. For example, the size of the nanoparticles corresponding to or smaller than the penetration depth can lead to a high refractive index according to the following formula 2:

[Formula 2]

유효 굴절률,

는 유효 유전율,

는 유효 투자율, a는 단위 구조체(유닛 셀)의 크기, g는 인접한 나노입자와의 간격인 갭의 폭을 의미한다. 메타물질 나노 복합구조체는 기하학에 의해 결정되는 정전용량 효과(capacitive effect)로 인해 광범위한 파장 범위에 걸쳐 거의 일정한 높은 유효 유전율을 갖는다. 일반적으로, 잘 알려지지 않은 (메타)물질의 DC 또는 저-주파수 유전율은, 플레이트 사이의 전체 공간을 채우는 테스트 물질을 갖는 평행플레이트 커패시터의 정전용량(capacitance)과 같은 규모(dimension)이지만 공지의 유전율을 갖는 기준 물질이 채워진 평행플레이트 커패시터의 정전용량을 비교함으로써 정량화될 수 있다. 평행플레이트 커패시터의 상기 정전용량이 C = Q/V = ε_cap 로서 표현될 때(C, Q, 및 V는 각각 정전용량, 총 전하, 및 총 전압 강하이고, 반면 ε_cap, A, 및 d는 각각 플레이트 사이의 유전물질의 유전율, 면적 및 거리임), 상기 정전용량은 ε_cap 에 정비례한다. 따라서, 상기 정전용량의 비율은 테스트 물질 및 기준 물질의 유전율의 비율이다. 메타물질 나노 복합구조체가 플레이트들 사이에 삽입되고, 전하 + Q 및 - Q가 커패시터 플레이트에 인가되는 경우, 상기 전하에 의한 종방향의 전기장이 금속 입자 사이의 갭 영역에서만 존재하고 입자의 내부로부터 배제될 것이며, 이것은 전형적으로 서브-옹스트롬(sub-angstrom)의 단위인, 종방향의 전기장이 토마스-페르미 스크리닝 길이를 넘어 금속 내로 침투할 수 없기 때문이다. 이 사실은 도 1의 (b)에 나타나있다. 메타물질 나노 복합구조체의 유전체 갭 영역에서의 전기장의 세기는 커패시터 플레이트 사이의 공간이 갭 유전체와 같이 동일한 물질(permittivity,

)로 채워진 기준 케이스에서 전기장의 세기와 동일하다. 전압 강하가 전기장의 선 적분이기 때문에, 메타물질 나노 복합구조체의 존재 하에서 총 전압 강하는 기준 케이스에서 전압 강하의 g/a로 감소되며, 이것은 상기 정전용량이 a/g만큼 향상되는 것을 의미한다. 따라서, 메타물질 나노 복합구조체의

가 또한 a/g만큼 향상되어

이 되는 것을 의미한다. 즉, 결과적으로 메타물질 나노 복합구조체가 고굴절률을 위해 '조밀하게 배열(close-packed)된' 어레이를 필요로 하는 것은 a/g인자로 인한 것이다.In this derivation,

Effective refractive index,

Is an effective permittivity,

Is the effective permeability, a is the size of the unit structure (unit cell), and g is the width of the gap, which is the gap with adjacent nanoparticles. The metamaterial nanocomposite structure has a substantially constant high effective dielectric constant over a wide range of wavelengths due to the capacitive effect determined by geometry. In general, the DC or low-frequency dielectric constant of an unknown (meta) material is the same as the capacitance of a parallel plate capacitor with the test material filling the entire space between the plates, but with a known permittivity Can be quantified by comparing the capacitance of the filled parallel plate capacitor with the reference material it has. A parallel plate when the capacitance is expressed as C = Q / V = ε _cap of the capacitor (C, Q, and V are respectively the capacitance, the total charge, and the total voltage drop, while ε _cap, A, and d The dielectric constant, the area and the distance, respectively, of the dielectric material between the plates), the capacitance is directly proportional to? _Cap . Thus, the ratio of the capacitance is the ratio of the dielectric constant of the test material and the reference material. When the meta-material nanocomposite structure is inserted between the plates and charges + Q and -Q are applied to the capacitor plate, the electric field in the longitudinal direction due to the charge exists only in the gap region between the metal particles, This is because the longitudinal electric field, which is typically a sub-angstrom unit, can not penetrate into the metal beyond the Thomas-Fermi screening length. This fact is shown in Fig. 1 (b). The strength of the electric field in the dielectric gap region of the meta-material nanocomposite structure is such that the space between the capacitor plates is the same material (permittivity,

), Which is the same as the intensity of the electric field in the reference case. Since the voltage drop is a linear integral of the electric field, the total voltage drop in the presence of the meta-material nanocomposite structure is reduced to g / a of the voltage drop in the reference case, which means that the capacitance is improved by a / g. Thus, the metamaterial nanocomposite structure

Is also increased by a / g

. That is, the result is that the meta-material nanocomposite structure requires a "close-packed" array for high refractive index because of the a / g factor.

In one embodiment of the present invention, the nanoparticles in the unit structure may be coated or wrapped by the host material, but the present invention is not limited thereto. For example, the unit structure may be a core-shell structure in which spherical nanoparticles are surrounded by a host material and then arranged in another host material, but the present invention is not limited thereto. For example, the unit structure may be formed by arranging nanoparticles in a cylindrical form such as carbon nanotubes in a host material, but the present invention is not limited thereto. For example, the array of nanoparticles may be, but not limited to, a core-shell structure or a close-pack.

In one embodiment of the present invention, the material of the nanoparticles is selected from the group consisting of Au, Ag, Al, Cu, Ni, Pt, Ti, (Sn), and combinations thereof, but it may not be so limited.

In one embodiment of the present invention, when the nanoparticles are semiconductors, the nanoparticles may exhibit a high refractive index even though the nanoparticles are larger in size, but the present invention is not limited thereto. In the case of semiconductor nanoparticles, the penetration depth of the nanoparticles is longer than that of the metal nanoparticles, so that the magnetic field penetrates deeper, and thus the nanoparticles may exhibit a higher refractive index even though they are larger in size than metal, .

In one embodiment of the invention, the nanoparticles in the unit structure comprise a material whose real part of the permittivity is negative, and the host material may include, but is not limited to, a material in which the real part of the permittivity is positive . For example, the nanoparticles may be formed of a metal such as gold (Au), silver (Ag), aluminum (Al), copper (Cu), nickel (Ni), platinum (Pt), titanium (Ti) matter; Two or more kinds of metal alloys; Carbon-based materials such as graphite, carbon nanotubes, and fullerene; (PbS), indium phosphide (InAs), indium phosphide (InP), indium antimonide (InSb), gallium phosphide (GaP), gallium nitride (GaN) Semiconductor materials such as gallium arsenide (GaAs); Or compound semiconductors of three or more kinds of elements such as InGaAsP, but the present invention is not limited thereto. For example, the host material may be selected from the group consisting of silicon dioxide (SiO ₂ ), copper oxide (CuO ₂ ), aluminum oxide (Al ₂ O ₃ ), vanadium oxide, titanium oxide, Oxides such as; Nitrides such as silicon nitride (Si ₃ N ₄ ), sialon and the like; (PbS), indium phosphide (InAs), indium phosphide (InP), indium antimonide (InSb), gallium phosphide (GaP), gallium nitride (GaN) Semiconductor materials such as gallium arsenide (GaAs); Compound semiconductors of three or more elements such as InGaAsP; Polymer material; Carbon-based materials such as graphite; Organic materials such as polydodamine, oleylamine; Or a liquid substance such as water, oil, organic solvent and the like, but the present invention is not limited thereto.

In one embodiment of the present invention, when the host material is a liquid substance such as water or oil, the host material may be applied to a sample using a spin coating method, a spray coating method, a dipping method, But may not be limited thereto.

In one embodiment of the present invention, the refractive index of the meta-material nanocomposite structure can be improved by using aluminum (Al), which is a highly reactive metal, as the nanoparticles, but the present invention is not limited thereto.

In one embodiment of the present invention, the nanoparticles in the unit structure may have a single crystal structure, such as a tetragonal, hexahedral, octahedral, tetragonal, tetragonal, transhedral, rodlike, concave tetragonal, , Hexagonal plate type, triangular plate type, circular pentagonal prism shape, twin prism shape, spherical shape, elliptical shape, and cylindrical shape, but may not be limited thereto.

In one embodiment of the present invention, the nanoparticles may have an isotropic spherical shape, a tetrahedral shape, a cubic shape, an octahedral shape, a quadrilateral shape, a tetragonal tetragonal shape, or a quadrilateral shape. But may not be limited.

In one embodiment of the present invention, the nanoparticles formed in the unit structure may have a gap width of about 10 nm or less, which is an interval between adjacent nanoparticles, but may not be limited thereto. For example, the width of the gap, which is the distance between the nanoparticles and adjacent nanoparticles, is about 10 nm or less, about 9 nm or less, about 8 nm or less, about 7 nm or less, about 6 nm or less, But may not be limited thereto.

In one embodiment of the present invention, the permittivity of the nanoparticles can be freely adjusted without noticeable change in permeability by varying the width of the gap while maintaining the size of the unit structure at a constant value under the penetration depth, . While the permeability is almost constant for nanoparticles, the dielectric constant is inversely proportional to the width of the gap, so that a high permittivity and a high refractive index can be achieved by reducing the width of the gap.

In one embodiment of the invention, the material in which the real part of the dielectric constant of the nanoparticles is negative is a material selected from the group consisting of a metal material, a carbon-based material, a semiconductor material having improved carrier density by doping, But it is not limited thereto. For example, the nanoparticles may be formed of a metal such as gold (Au), silver (Ag), aluminum (Al), copper (Cu), nickel (Ni), platinum (Pt), titanium (Ti) matter; Two or more kinds of metal alloys; Carbon-based materials such as graphite, carbon nanotubes, and fullerene; (PbS), indium phosphide (InAs), indium phosphide (InP), indium antimonide (InSb), gallium phosphide (GaP), gallium nitride Semiconductor materials such as gallium arsenide (GaAs); Or compound semiconductors of three or more kinds of elements such as InGaAsP, but the present invention is not limited thereto.

In one embodiment of the invention, the material in which the real part of the dielectric constant of the host material is positive is selected from the group consisting of oxides, nitrides, semiconductor materials of low charge density, polymeric materials, organic materials, liquid materials, But are not limited thereto. For example, the host material may be selected from the group consisting of silicon dioxide (SiO ₂ ), copper oxide (CuO ₂ ), aluminum oxide (Al ₂ O ₃ ), vanadium oxide, titanium oxide, Oxides such as; Nitrides such as silicon nitride (Si ₃ N ₄ ), sialon and the like; (CdTe), lead sulfide (PbS), indium phosphide (InAs), indium phosphide (InP), indium antimonide (InSb), gallium phosphide (GaP), gallium nitride (GaN) Semiconductor materials such as gallium (GaAs); Compound semiconductor materials of three or more kinds of elements such as InGaAsP; Polymer material; Carbon-based materials such as graphite, carbon nanotubes, and fullerene; Organic materials such as polydodamine, oleylamine; Or a liquid substance such as water, oil, organic solvent and the like, but the present invention is not limited thereto.

In one embodiment of the present invention, when the host material is a liquid substance such as water or oil, the host material may be applied to a sample using a spin coating method, a spray coating method, a dipping method, But may not be limited thereto.

The second aspect of the present invention provides an optical film comprising the meta-material nanocomposite structure according to the first aspect.

In one embodiment of the present invention, the meta-material nanocomposite structure includes unit structures including nanoparticles and a host material. The unit structure may be three-dimensionally closely packed, But may not be limited thereto.

In one embodiment of the present invention, the optical film may be, but not limited to, using a high refractive index to improve the resolution of an optical system, such as a photolithography or optical microscope.

In one embodiment of the present invention, the optical film may be formed using a vapor deposition method, a spray method, a dipping method, a drip method, or the like, but may not be limited thereto.

Although the second aspect of the present invention has not been described in detail for the first aspect of the present invention, the description of the first aspect of the present invention may be applied to the second aspect of the present invention, have.

In the present application, a three-dimensionally densely arranged metal nanoparticle array has been proposed to achieve wideband high refractive index in the visible and infrared regions. In a densely arranged meta-material nanocomposite structure, a small gap-to-period ratio is connected from the strongly enclosed electric field within the dielectric gap to a more effective effective permittivity. At the same time, the tens of nanometers in diameter of the metal particles prevent the lowering of the uninvited effective permeability, since the size of the nanoparticles corresponding to or smaller than the penetration depth allows penetration of the magnetic field through the metal particles. This difference in electrical and magnetic field behavior is due to a large difference between the Thomas-Fermi screening length and penetration depth. As a result, the effective refractive index of the meta-material nanocomposite structure is much higher than that of natural materials in the visible and infrared regions and can be easily controlled by changing the width of the gap. The proposed metamaterial nanocomposite structure overcomes the bandwidth limitations of other metamaterials that directly depend on surface plasmon resonance. Another advantage of the metamaterial nanocomposite structure is the weak dependence of the effective refractive index on the particle shape and lattice type, allowing for the possibility of multiple bottom-up particle synthesis methods in lieu of expensive and complex top-down nanofabrication processes. Since the ability to control the permittivity and permeability is important not only in achieving high refractive indices but also in designing other optical properties of impedances and materials, the proposed technique can be used in immersion lenses for lithography and imaging as waveguide couplers, modulators, photodetectors, and energy devices.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are given to aid understanding of the present invention, and the present invention is not limited to the following examples.

[Example]

Example 1: FDTD simulation analysis

FDTD simulation conditions

A finite difference time domain method simulation (FDTD simulation) was performed using the product of Lumerical Solutions (version 8.7.4). The entire FDTD simulation proceeded in three dimensions. 2, a schematic diagram of FDTD simulation on the XZ plane of the meta-material nanocomposite structure is shown. The light having X-polarized light propagates along the Z-direction, and the range of the light source wavelength is 200 nm to 3,000 nm. Since the metamaterial nanocomposite structure is composed of repeated unit structures in the XY plane, periodic boundary conditions are used in the X- and Y-directions to save computer time. On both sides in the Z-direction, a perfectly matched layer (PML) was used. Two monitors were placed below and above to characterize the metamaterial nanocomposite structure using the S-parameter method. In all simulations, the minimum mesh size was designed to be one tenth the size of the smallest structure. In addition, the size of the minimum mesh is designed by proceeding with convergence test first. For gold metamaterial nanocomposite structure simulations, Johnson and Christy material data are applied at 200 nm to 3,000 nm. The Palik material data is used for simulation of silver and aluminum metamaterial nanocomposite structures, and material data such as refractive index for the materials (gold, silver, and aluminum) used in the simulation are plotted in FIG. Silicon dioxide was selected as the dielectric host material with a refractive index of 1.473.

1-1: The "G" magnetic field distribution of the nanocomposite structure with the nanoparticle size

인 고굴절률을 실현할 수 있다.FDTD simulation was used to confirm the refractive index change according to the nanoparticle size of the metal. As shown in FIG. 4, a perfect electric conductor (PEC) and gold were compared for metal materials. 4 (a), 4 (d) and 4 (g) are schematic diagrams of the structure of the nanocomposite structure of meta-material, and red squares represent one unit structure. 4 (b), (e), and (h) show the Ex-field distribution of one meta-material nanocomposite structure unit structure in the z-normal view as shown in Fig. , (f), and (i) show the Hy-field distribution. The Ex-field and Hy-field distributions are normalized by the maximum value at the edge of the unit structure, which is consistent with the red squares in Figs. 4 (a), (d), and (g). The center coordinate of the unit structure cross section is typically (0, 0). The PEC had a Thomas-Fermi screening length and penetration depth of 0, and the particle size was always greater than both lengths. The lengths of gold in the near-infrared and visible wavelengths above the interband transition wavelengths were sub-angstrom scale and 22 nm, respectively. Thus, two cases with different particle sizes of 18 nm and 270 nm were compared. This was smaller and larger than the depth of penetration, respectively. The particle size to gap ratio was fixed at 9: 1. As shown in Figures 4 (b), (e), and (h), the electric field was strongly localized in the dielectric gap between the metal particles regardless of the metal particle size and the metal was clearly identified as PEC or gold. This is because the Thomas-Fermi length is much shorter than both the particle and gap widths in the three cases. Because of this confinement, the effective permittivity should be close to 10 times that of the dielectric in all three cases. In contrast, magnetic field distribution varies considerably with matter and size. As shown in Fig. 4 (c), the magnetic field was only present outside the PEC particles. It exhibits strong antiferromagnetic characteristics. In the case of gold particles, the magnetic field penetrated into the particles. Empirically, this distribution could be investigated as a hyperbolic cosine function of the first order. Thus, when the size of the gold particles is larger than the penetration depth, the magnetic field largely fails to penetrate most of the interior region of the particle, and the field profile exhibits strong diamagnetism and is close to that of the PEC particle (FIG. However, when the size of the gold nanoparticles is 18 nm (unit structure size 20 nm, gap 2 nm) and the normalized to the maximum value in the dielectric gap, the magnetic field has a minimum value of 0.9465 at the center of the nanoparticle, (Fig. 4 (f)). Therefore, the size of the metal nanoparticles corresponding to or smaller than the penetration depth of the nanoparticles is an important key for inducing magnetic penetration through the metal, which prevents a significant decrease in the effective permeability of the metamaterial nanocomposite structure Directly. The result of the magnetic field corresponds to the idea proposed in Fig. 1 (c), and the penetration depth corresponding to the metal particles is

A high refractive index can be realized.

1-2: Determination of the refractive index of a metamaterial nanocomposite structure

) 및 투자율(

)을, 도 5의 (b)는 유효 굴절률 및 FOM의 실제, 허수 부분을 나타낸다. 단위 구조체 크기 및 갭의 폭은 각각 20 nm 및 2 nm이었으며, 사용된 호스트 물질은 SiO₂이었다. 도 5의 (a)에서 상단의 녹색 및 하단의 붉은색 점선은 메타물질 나노 복합구조체의 유효 유전율 및 투자율의 점근선이다. 도 5의 (b)에서 녹색 점선은 메타물질 나노 복합구조체의 유효 굴절률의 점근선이다. 메타물질 나노 복합구조체는 800 nm 부근에서 두드러진 공명 특성을 나타내며, 공명 피크 이후 넓은 파장 범위에 걸쳐 거의 일정한 매우 높은 굴절률을 나타낸다는 것이 확인되었으며, 이것은 입자의 형태 및 크기에 의해 조절될 수 있는 나노입자의 쌍극 공명(dipolar resonance)으로 인한 것이다. 도 5에서 점선으로 표시된, 장-파장 한계에서 유효 물질 파라미터의 점근값(asymptotic value)은 이론적 예측에 매우 가까웠다. 점근선의 유전율, 투자율, 및 결과 굴절률은 21.2, 0.983, 및 4.57이었으며, 그에 대한 이론상의 값은

=(20/2)×2.17=21.7, 0.998, 및 4.65이었다.

로서 정의된 성능 지수(figure of merit, FOM)는 가시광 및 근적외선 영역에서 메타물질에 대해 상당히 높으며, 이것은 현재의 디자인 연구가, 공명 및 관련된 강한 분산에 직접 의존하는 종래 제안되었던 메타물질의 대부분과 달리, 공명으로부터 무관하다는 사실에 주로 기인된 것이다.For quantitative analysis, the s-parameter extraction method was used to calculate the effective material property values from the FDTD simulation. The extracted effective values of refractive index, permittivity, and permeability for a gold metamaterial nanocomposite structure with a 20 nm unit structure and a 2 nm gap filled with SiO ₂ were plotted in FIG. 5 (a) shows the effective permittivity of the gold metamaterial nanocomposite structure (

) And permeability (

, And FIG. 5 (b) shows the actual and imaginary parts of the effective refractive index and the FOM. The unit structure size and the gap width were 20 nm and 2 nm, respectively, and the host material used was SiO ₂ . In FIG. 5 (a), the red dotted line at the upper green and the red dot at the lower end are asymptotes of the effective permittivity and permeability of the meta-material nanocomposite structure. In FIG. 5 (b), the dotted green line is the asymptote of the effective refractive index of the meta-material nanocomposite structure. It has been found that the meta-material nanocomposite structure exhibits remarkable resonance characteristics near 800 nm and exhibits a substantially constant very high refractive index over a wide wavelength range after the resonance peak. This is because the nanoparticles Which is due to the dipolar resonance. The asymptotic value of the effective material parameter at the long wavelength limit, shown in dashed lines in Fig. 5, is very close to the theoretical prediction. The permittivity, permeability, and resulting index of asymptotes were 21.2, 0.983, and 4.57,

= (20/2) x 2.17 = 21.7, 0.998, and 4.65.

, The figure of merit (FOM) is fairly high for metamaterials in the visible and near-infrared regions, which indicates that current design studies have shown that, unlike most of the previously proposed metamaterials, which are directly dependent on resonance and associated strong dispersion , Which is largely due to the fact that it is independent of resonance.

1-3: Refractive Index Control of Metamaterial Nanocomposite Structure

) 또는 매우 높은 어드미턴스(admittance) (

) 및 중간의 어떠한 것을 갖는 광대역 메타물질을 설계할 수 있다.FDTD simulation was used to confirm the refractive index of the nanocomposite structure of the metamaterial nanocomposite structure according to the size of the unit structure and the width of the gap. The magnetic and electrical properties of the metamaterial nanocomposite structure can be controlled independently because the permeability is highly dependent on the relative size of the particles relative to the penetration depth, whereas the dielectric constant is not. As shown in FIG. 6, the dielectric constant can be freely adjusted without noticeable change in permeability by changing the width of the gap while maintaining the size of the unit structure at a constant value of 20 nm under the penetration depth (FIG. 6 (a) (C). It can be seen that the permeability is almost constant for the gold metamaterial nanocomposite structure, while the dielectric constant is inversely proportional to the width of the gap. Thus, a high permeability and a high refractive index can be achieved by reducing the width of the gap. In order to maintain the same permittivity, the magnitude of the magnetic characteristic is changed by changing the size of the unit structure while maintaining the ratio between the size of the unit structure and the width of the gap at a constant ratio of 10: 1, (Magnetic permeability near 0) (FIG. 6 (d) to (f)). This theoretical prediction, based on geometry and gold penetration depth, is in good agreement with the FDTD results further validating our model. In comparison, when the Thomas-Fermi length is not negligible in both cases, the permittivity almost coincides with the gold metamaterial nanocomposite structure, whereas the PEC and PEC with a penetration depth of 0 instead of 22 nm gold The nanomaterial structure of the metamaterial shows a very different permeability. Utilizing this independent control of electrical and magnetic properties, very high refractive index (

) Or very high admittance (

Lt; / RTI > and any of the middle.

1-4: Gold, silver, and aluminum metamaterial nanocomposite structures

FDTD simulations were performed on gold, silver, and aluminum to verify that the theoretical model and analysis also apply to other metals. The results were compared in Table 1 and they showed that the valid values were not significantly different, which is due to the fact that these metals have similar penetration depths. However, the resonance wavelength is affected by the surface plasmon frequency and is remarkably short for the aluminum metamaterial nanocomposite structure. This means that although the aluminum has a small FOM due to large optical losses, the aluminum meta-material nanocomposite structure with a 20 nm particle size is capable of broadband high refractive index in the visible range. It is also an optically transparent host medium that can utilize various types of dielectrics. Since the effective refractive index of the meta-material nanocomposite structure is continuously proportional to the refractive index of the host medium, a higher effective refractive index can be achieved if the meta-material nanocomposite structure is embedded in a host material having a higher refractive index than SiO ₂ .

1-5: Comparison of Refractive Index According to Grid Pattern

To confirm the refractive indices of the metamaterial nanocomposite structures in different lattice forms, FDTD simulations were performed. Although the meta-material nanocomposite structure of this embodiment is assumed to be a cubic lattice and a cubic particle, the principle remains the same for other particle types and lattice types, and the high refractive index is maintained in a densely arranged configuration, And is achieved by sub-skin-depth-scale particles. For comparison, spheres in a hexagonal lattice were considered. FIG. 7 (a) is a multi-layer schematic diagram of a cubic nanoparticle in a cubic lattice, and FIG. 7 (b) shows a nanosphere in a hexagonal array included in a host material. 7C is a result of the multi-layer FDTD of the gold cube, and the size and the width of the unit structure of the gold cube are 20 nm and 2 nm, respectively. Fig. 5 (d) is a result of multi-layer FDTD of gold spheres, the sphere diameter and the center-to-center distance are 19 nm and 20 nm, respectively. In Figures 7 (c) and 7 (d), 1 to 20 indicate the number of layers. One subtle point is that the mono-layer of the sphere is not the true unit structure of the lattice, which also includes the truncated sphere from the top and bottom layers. Thus, in contrast to the gold-cube-shaped meta-material nanocomposite structure in Figure 7 (c), which is all data in a long wavelength regime closely overlapped with another, regardless of the number of layers, The extracted refractive indices of the meta-material nanocomposite structure of the sample showed a layer-number dependence on a thin sample (Fig. 5 (d)). However, for samples with five or more layers of spheres, the effective refractive index was nearly saturated and its intestinal-wavelength value was 4.10, which was significantly different from that of the cube-shaped metamaterial nanocomposite structure (4.48) I did not see it. This insensitiveness of the effective refractive index to the precise particle morphology enables various applications of previously reported metal nanoparticle synthesis methods.

Example 2: Fabrication of actual meta-material nanocomposite structure

2-1: Manufacture of hole pattern by block copolymer lithography

To create a very small nanoscale structure, a hole pattern was made using BCP lithography, as can be seen in Fig. The 4-inch silicon wafers were cleaned using an ultra-sonic bath. Washing was carried out in the order of deionized water, acetone, isopropyl alcohol, DI water wafer for 15 minutes, respectively. To make the substrate more hydrophilic, UV-ozone treatment was carried out for 30 minutes. Prior to coating PS-b-PMMA, a random brush solution was coated to modify the surface morphology of the substrate. The average value (Mn) of the molecular weight of the (PS-r-PMMA) -OH random brush was 8 kg mol with 62% of styrene (Sigma Aldrich) ^{- 1} . The substrate was then thermally annealed at 160 DEG C for 12 hours in a vacuum oven. 2 wt% PS-b-PMMA solution was spin-coated at 2,500 rpm for 1 minute on the surface-modified wafer. The PS-b-PMMA block copolymer had Mn of 140 kg mol ^-1 and 65 kg mol ^-1 for PS and PMMA blocks, respectively. Was selected to fabricate a cylinder structure with a diameter of 30 nm. The solution was dissolved in toluene solvent, 2 wt%. The coated wafer as described above was thermally annealed at 250 DEG C for 6 hours in a vacuum oven to produce a periodic cylinder pattern.

After the thermal annealing process at 250 ° C, the BCP (diblock-copolymer) coated wafer was exposed to UV light (UV cross-linker, Spectronics) at 2 J to decompose the PMMA microphase and solidify the microphase . The wafer was stored in an acetic acid solution (99.9% purity, Junsei corp.) For 10 minutes and then rinsed with deionized water for 10 minutes to remove the PMMA microphase. Acetic acid selectively removes the degraded PMMA, so after the chemical etching process, a hole pattern of 30 nm was uniformly produced on the wafer.

2-2: Preparation of aluminum nanocomposite structure

In order to fabricate an aluminum nanocomposite structure, an ion milling method was used as shown in FIG. The hole pattern of 30 nm produced was separated from the original substrate using hydrofluoric acid (49% to 51% HF solution, JT Baker.). The separated hole pattern was transferred onto the aluminum thin film surface. The aluminum thin film was deposited on a transparent quartz substrate by vapor deposition. The aluminum thin film is deposited in a high vacuum state (resistance method, 10 ^-7 torr). After the hole pattern was transferred onto the aluminum surface, oxygen reactive ion etching (RIE) was performed for 10 seconds to adjust the hole diameter and remove the PMMA residue on the substrate. Therefore, the diameter of the hole was enlarged to 40 nm after the RIE process.

Alumina (Al ₂ O ₃ ) was deposited on the hole pattern transferred by vapor deposition under the same conditions as the aluminum thin film. By ultrasonication in a toluene bath, the BCP hole pattern with the PS domain was removed from the aluminum surface. After removal of the polymer domains, only the alumina nanocomposite structure for the ion milling mask on the aluminum surface was left. The ion milling process was followed by a nanoscale hardmask and an alumina nanocomposite structure was fabricated. The chamber base was operated at less than 8 × 10 ^-7 torr and the process vacuum was conducted at less than 2 × 10 ^-4 torr with Ar gas of 6 sccm. The ion beam was accelerated by 100 V, 1 mA and the ion milling time was 5 to 12 minutes.

2-3: SEM analysis

A field emission scanning electron microscope (FE-SEM, HITACHI) was used to observe the surface and lateral morphology of the fabricated aluminum nanocomposite structure. All of the samples produced had tens of nanometers in size, and thus no osmium or platinum coatings were present on the samples. Since the thickness of such a conductive material coating is tens of nanometers or more, the sample was observed without coating to prevent distortion of the surface morphology. 10 (a) is a plan view of a hole pattern produced by a PS-b-PMMA block copolymer, and FIG. 10 (b) is an SEM image of an alumina hard mask periodically arranged on an aluminum thin film. 10 (c) and 10 (d) are samples produced by the ion milling process. From the SEM images, it can be seen that the aluminum nanocomposite structure was fabricated using a very similar scale BCP hole pattern.

2-4: AFM analysis

The surface morphology of the aluminum nanocomposite structure was examined using an atomic force microscope (AFM, XE-100, Park System and AFM, Nanoman, Veeco Instruments Inc.). The atomic force microscope creates a surface image by moving the probe over the surface of the sample. The probe is composed of a cantilever with a well defined resonant frequency and a tip with a very sharp tip. When the tip is close to the surface it is pulled or repelled. Any change in vibration amplitude or frequency tip is converted to a topo-graphic map. Surface morphology such as root-mean-square surface roughness, particle analysis, and line profile were analyzed. The surface topography of the differently fabricated aluminum nanostructures is shown in FIG. 11 (a) is an AFM image showing an aluminum nano-hemispherical composite structure using a 10 nm aluminum film for ion milling and FIG. 11 (b) is an AFM image showing an aluminum nano-hemispherical composite structure using a 20 nm aluminum film. As shown in Fig. 11, the surface of the fabricated aluminum nanocomposite structure is in good agreement with the SEM analysis result. The height of the two samples showed similarity. Since the thinner aluminum film reduces the time for ion milling, the alumina nano-dots used in the mask during the ion milling process may remain high. The height analyzed by AFM thus showed similarity between 10 nm samples of aluminum and 20 nm samples.

2-5: Transmittance measured with a UV-VIS spectrometer

To observe the optical properties of the fabricated samples, the transmittance and reflectance were measured (Lambda 1050, PerkinElmer). The samples were prepared on a transparent quartz substrate and all samples were> 1 cm ² in size. All data are generalized to the transmittance and reflectance of the quartz substrate. The range of the measured wavelength was 175 nm to 750 nm. This was measured at the KAIST Analysis Research Center. 12 shows the transmittance measured with a UV-VIS spectrometer at 175 nm to 750 nm, as shown in FIG. Samples with aluminum foil (thin film) of 10 nm thickness exhibit a sharper peak at 195 nm and samples with 20 nm aluminum foil exhibit broad peaks at 190 nm to 220 nm. Over the visible wavelength, all samples exhibited a clear characteristic, and the measured transmittance of a 10 nm aluminum sample was also nearly 100%. 20 nm aluminum samples showed low transmittance. The difference in optical properties between the two samples is in the enhanced absorption of the nanocomposite structure with an aluminum thickness incensement.

2-6: FDTD  Electromagnetic analysis using simulation

The aluminum nanocomposite structure thus prepared was analyzed by FDTD simulation. In the FDTD simulation, the structure was estimated to be a natural aluminum oxide layer of 3 nm. 13 shows the transmittance calculated numerically by FDTD simulation at 150 nm to 800 nm. The transmittance showed a difference between the measured and numerically calculated results. In Figure 13, the depth of the permeability was deeper than the measured result. The wavelength of the depth position was also the red-shift of the numerical simulation results and the 10 nm aluminum sample showed a sharp peak at 220 nm where the measured result was 195 nm. While the measured result showed one large peak at 190 nm with a small shoulder peak at 220 nm, the 20 nm aluminum sample showed two broad peaks in the transmission spectrum. This difference comes from the structural difference between the FDTD simulation and the fabricated sample. In the simulation, the aluminum nanocomposite structure was assumed to have a diameter of 40 nm, a center-to-center distance of 60 nm, and the structure was assumed to be perfectly periodic and symmetric. The optical response is highly dependent on the nanocomposite structure, and small differences in the structural dimension can cause different optical responses. The fabricated sample has both a particle size distribution and a center-to-center distribution. In addition, since aluminum plasmons are highly dependent on the deposition environment and the oxygen content of the aluminum nanocomposite structure affects the plasmonic reaction, it is difficult to accurately reproduce the aluminum nanocomposite structure by numerical simulation.

Although the fabricated structure has a gap of 20 nm, the aluminum hemispherical nanocomposite structure realized by BCP lithography exhibits optical characteristics similar to the simulation results, although it differs from the proposed densely arrayed unit structure. In Fig. 14, the effective refractive index was derived from a numerical simulation. As the height increases, the width of the gap decreases because the diameter of the structure is constant at 40 nm. Therefore, a sample with a thickness of 20 nm exhibits a higher effective refractive index value. Although the above derived value is not high, it shows the feasibility of a simple structure of visible meta material. As can be seen from the simulation, if the gap of the current sample at 20 nm level is reduced to 10 nm or less, a higher refractive index can be obtained .

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention.

Claims (17)

Comprising nanoparticles and unit structures comprising a host material,
Wherein the unit structures are arranged in three dimensions.
Metamaterial nanocomposite structure.
The method according to claim 1,
Wherein the meta-material nanocomposite structure has a high refractive index in a wavelength band selected from visible light, ultraviolet light, infrared light, and combinations thereof.
3. The method of claim 2,
Wherein the meta-material nanocomposite structure has a maximum refractive index of 1.5 or more at a wavelength of 200 nm or less.
3. The method of claim 2,
Wherein the meta-material nanocomposite structure has a maximum refractive index of 2 or more at an ultraviolet wavelength of 200 nm to 400 nm.
3. The method of claim 2,
Wherein the meta-material nanocomposite structure has a maximum refractive index of 4 or more at a visible light wavelength of 400 nm to 700 nm.
3. The method of claim 2,
Wherein the meta-material nanocomposite structure has a maximum refractive index of 5 or more at an infrared wavelength of 700 nm or more.
The method according to claim 1,
Wherein the nanoparticles in the unit structure are surrounded by the host material.
The method according to claim 1,
Wherein the nanoparticles in the unit structure comprise a material whose real part of the permittivity is negative, and the host material comprises a material whose real part of the permittivity is positive.
The method according to claim 1,
Wherein the size of the nanoparticles in the unit structure corresponds to or is smaller than the depth of penetration of the nanoparticles.
The method according to claim 1,
Wherein the unit structure is three-dimensionally arranged with an isotropic or anisotropic property.
The method according to claim 1,
In the unit structure, the nanoparticles may have a shape selected from the group consisting of a tetragonal, hexahedral, octahedral, tetragonal, tetragonal, icosahedral, rod-shaped, concave tetragonal, square, twin, spherical, Wherein the meta-material nanocomposite structure comprises a nanocomposite structure.
The method according to claim 1,
Wherein the nanoparticle comprises an isotropic spherical shape, a tetrahedral shape, a cube shape, an octahedral shape, a quadrilateral shape, a tetragonal tetrahedral shape, or a quadrilateral shape.
The method according to claim 1,
Wherein the nanoparticles in the unit structure are spaced apart from adjacent nanoparticles by 10 nm or less.
9. The method of claim 8,
Wherein the material having a negative real part of the permittivity of the nanoparticles comprises a material selected from the group consisting of a metal material, a carbon-based material, a semiconductor material having improved carrier density by doping, and combinations thereof. Nanocomposite structure.
9. The method of claim 8,
Wherein the material in which the real part of the dielectric constant of the host material is positive comprises a material selected from the group consisting of oxides, nitrides, semiconductor materials of low charge density, polymeric materials, organic materials, liquid materials, Metamaterial nanocomposite structure.
The meta-material nanocomposite structure according to any one of claims 1 to 15
And an optical film.
17. The method of claim 16,
Wherein the optical film improves resolution of the optical lithography or optical microscope by using a high refractive index.

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